The algorithm capable of tracking air pollution by sector and geographic area has arrived. It is called ORSA (On-line Reactive Source Apportionment), and has been developed by ENEA to identify the origin by sector and geographic area of pollutant emissions, keeping track of the origin even during chemical and physical transformations in the atmosphere. Thanks to the support of the Ministry of the Environment and Energy Security and the company Arianet, the ORSA algorithm is already operational in the ENEA air quality monitoring system MINNI, which provides daily forecasts of the main concentrations of gases and particulates in the lowest layers of the atmosphere (three-day for Italy and four-day for Europe). Currently, there are so-called emission inventories, compiled by law by environmental agencies, which catalog and calculate the mass quantity of each pollutant impacting health and the environment (nitrogen oxides, sulfur oxides, dust, volatile organic compounds, ammonia, heavy metals) emitted by different sources.